The telecommunications industry has evolved greatly over the past 30 years. Telecommunications developed from service providers delivering analog telephone services to homes and businesses. The analog telephone services initially limited telephones to be connected directly to telephone wires. These telephones had a base unit and a handset connected to the base unit via a cord. Cordless telephones were later developed to allow users to talk on the telephone while moving freely about his or her house or in the local vicinity. The cordless telephone is basically a combination of a telephone and a radio transmitter/receiver and has two components, a base and a handset. The base is attached to the public switched telephone network via a wire connection. The base receives an incoming call from the public switched telephone network and converts it to an FM signal, which is locally broadcast. The handset also includes a receiver/transmitter to receive the FM radio signals from the base, convert the radio signals to sound for the user of the handset to hear the other person's speech and broadcast speech spoken into the handset by the user back to the base for communication back to the other person via the public switch telephone network.
Initially, around 1980, the FM signals were broadcast at a frequency of 27 megahertz (MHz). In 1986, the frequency range was increased by the Federal Communications Commission (FCC) to be between 47 and 49 MHz. These early cordless wireless telephones had problems, such as limited range, poor sound quality, and poor security. In 1990, the FCC granted a frequency range of 900 MHz, which increased the range and clarity of the signals due to having more channels within the range. In 1994, digital cordless phones were introduced, which improved the sound quality and increased security. In 1995, Digital Spread Spectrum (DSS) was introduced for cordless telephones. DSS greatly improved security to prevent eavesdropping of telephone calls. In 1998, the frequency range of cordless telephones was increased by the FCC to 2.4 and 5.8 gigahertz (GHz). As understood in the art, these different communication techniques (i.e., analog and digital) are known as local, cordless telephone communications protocols.
There are currently 110 million households in the United States. At present, 48 million households have broadband communications delivered by service providers. Broadband communications enable high speed Internet access, but also enable digital cordless telephone capabilities, including voice over IP (VoIP).
While cordless telephones made great strides over the years, mobile telephones or cell phones were also developing during that time period. Initially, analog cell phone communications were developed. One standard was known as advanced mobile phone service (AMPS). Over time, digital mobile communications were developed. These digital communications included a number of different mobile communications protocols, including Time Division Multiple Access (TDMA), Code Division Multiple Access (CDMA), and Global System for Mobile Communications (GSM). For the most part, TDMA and CDMA have been adopted in the United States while GSM is more heavily utilized in Europe. Because of the different standards, handset makers adopted mobile handsets or telephones for the particular mobile communications protocols. To accommodate service providers and customers, handset makers eventually adopted handsets to be able to communicate over multiple mobile protocols. For example, mobile telephones are now widely available to communicate over the AMPS, CDMA, and GSM mobile communications protocols. These tri-mode telephones enable subscribers to roam in various areas of the United States and Europe and communicate over different telecommunications networks using the different wireless communications protocols.
More recently, wireless fidelity (WiFi) communications have been developed to enable computers to communicate over the Internet via WiFi access points. These WiFi access points were originally deployed in public venues, such as coffee shops, airports, and other locations to enable customers of those locations to communicate over the Internet with their computers. One reason for public deployment is the cost of the WiFi access points. More recently, WiFi access points have come down in price and are now being deployed in houses to enable computer users to access the Internet wirelessly from their computers, thereby eliminating the need to have a computer connected to a cable within a house. Although less expensive, the WiFi access points are still relatively expensive so that, relatively speaking, few homes have WiFi access points.
With this new form of wireless communication, handset makers have begun developing telephones that are capable of communicating over WiFi access points. Some of the handsets are limited to WiFi communications, but other handsets have begun integrating mobile telephone communications (e.g., CDMA and WiFi communications). There are a number of problems with WiFi. First, the handsets are expensive. Another problem that exists with WiFi telephone communications is that the WiFi voice quality is well below that of other forms of wireless communications. Studies have shown that PSTN communications and, more recently, VoIP communications receive about a 4.5 or 4.6 mean opinion score (MOS) out of a maximum 5.0 score, mobile telephone CDMA communications receive about a 3.5 or lower MOS, and WiFi communications receive about a 3.0-3.5 MOS. These phones that have been developed seek to benefit subscribers or users of these WiFi compatible handsets by public availability (e.g., coffee shops) and that the technology currently exists. While a cost savings may occur from the mobile communications service provider due to being able to switch to a WiFi communications network, WiFi communications still cost money to access, although a lower monthly-fixed fee than mobile communications. Another problem that exists with WiFi is security, as WiFi is generally an open protocol that enables others with scanners to be able to listen to telephone calls made over unprotected WiFi connections. If a user desires to use WiFi at home, a costly set top box and WiFi access point is needed.
One problem that may be encountered by cordless phones occurs when the cordless phone is located near the edge of the cordless telephone's signal range. TIA/EIA-470-C is a standards document that describes recommended cordless telephone range measurement procedures. Through use of these procedures, ranges of cordless telephones can be determined. Even with these standards defined procedures, practically speaking, not all cordless telephones perform to meet the specifications due to a variety of reasons, such as environmental (e.g., position of base unit with respect to other objects) or cordless phone operations (e.g., low battery). Also, different cordless telephones, even different models produced by the same manufacturer, are often found to have different ranges.
Another common issue with wireless devices involves battery life. For multimode wireless devices, when one communication protocol is being used, features that are not needed from another protocol, such as a signal level boost used for cellular telephones, will remain operable even though the phone is no longer using that protocol. This shortens the time the handset can be used between charges and causes unnecessary energy consumption.